Commercially available spas typically have a spa cover to prevent dirt or dust from entering therein. To open the spa, a spa cover is typically folded in half, hingedly lifted off the top of the spa, and lowered vertically behind the spa so as to reduce its obstruction of view to a person using the spa. However, such lowering and stowage of the spa cover typically requires an area behind the spa that may be larger than available in a small backyard.
To accommodate those without sufficient room to stow the spa cover behind the spa, some spa covers are kept in an upright position when the spa is fully open. This way, less room is typically required behind the spa. However, spa covers in an upright position are more susceptible to a gust of wind that blows against it from the rear or other forces that tend to close the spa cover when an occupant is in the spa.
U.S. Patent Publication No. 2002/0050003 filed by Perry (“Perry I”) discloses a gas spring lock for engaging and locking a gas spring in the extended position so that covers of spas, hot tubs and other similar apparatus that employ gas springs can be safely locked into an open position.
U.S. Pat. No. 6,000,071 issued to Fettes (“Fettes I”) discloses an apparatus for aiding removal and replacement of a spa cover. Fettes I discloses a lifting system for exerting a lifting force on an arm attached to the spa cover, tending to lift the arm as the arm moves from the covering position toward the uncovering position, and for exerting a resistance force on the arm tending to resist movement of the arm from the uncovering position toward the covering position.
U.S. Pat. No. 5,950,252 issued to Fettes (“Fettes II”) discloses a device for aiding in the removal and replacement of a spa cover atop a spa tub. FIGS. 11–13 disclose a spa cover that is stowed at an upright position.
U.S. Pat. No. 5,689,841 issued to Black et al. (“Black et al.”) discloses a spa cover lifting apparatus which can be adjusted to accommodate spa covers of different sizes. The lifting action of the apparatus is assisted by a telescoping gas strut.
In each of the above publication and patents, a gas spring forms an angle that is more than 45 degrees with respect to the top of the spa when the spa cover is in a fully open position.
U.S. Pat. No. 5,819,332 issued to Perry (“Perry II”) discloses a spa cover removal apparatus. As seen in FIG. 8, the gas spring 63 can assume an infinite number of positions thereby providing a wide range of adjustment for the amount of load it assumes to resist.
U.S. Pat. No. 4,899,420 issued to Bye et al. (“Bye et al.”) discloses a hinge system for a large or heavy cover member hinged to a container member. A container hinge plate is secured to a side wall of the container member. A cover hinge plate is secured to a side wall of the cover member and rotatably connected to the first hinge means at a hinge pivot means. Bye et al. also discloses a gas strut that appears to form an angle that is less than 45 degrees with respect to a horizontal plane. The cover member pivots with respect to the container member about the same axis as the axis of rotation between the container hinge plate and the cover hinge plate.
U.S. Pat. No. 6,195,811 issued to Dragovic (“Dragovic”) discloses a spa cover mounting method and apparatus. Dragovic discloses that a foam spa cover member is attached to a cover lifter apparatus using a plurality of brackets.